winter tires?

[mcurcio1989]

I am sure this has been discussed but the search function is coming up empty. Do you guys find winter tires to be necessary for driving in the snow. I am switching over from a 325xi which I thought handled awesome in the snow. Yesterday we got our first snow and I had to take the old xi out for a test drive after doing vanos seals (before I sell it) naturally I had to play around in the snow a little. After finishing up I grabbed the x5 to see how she would like the snow and it sort of seemed like it didn't have the same grab on stops as the xi but better traction from a take off. Not sure if the braking is due to the fact that there is a little less tread left on the x5 tires or if maybe this vehicle just needs winter tires to handle properly. I have a set from the PO (who lived way further north than me) that I was planning on selling but I am wondering if I should think twice. He only had the tires and not rims so it is sort of a hassle.